Arthroscopy is a minimally invasive surgical technique for removing diseased or damaged tissue from intra-articular regions of the body, such as the shoulder, hip, wrist, knee, and spine. Arthroscopic shavers can be used to remove bone, cartilage, and other soft tissue from a patient's joint with less surgical trauma to the joint than conventional surgical techniques. Typically, an arthroscopic shaver is an electro-mechanical device that includes a hand piece and an elongate shaft that houses a cutting assembly. The cutting assembly can be positioned at a distal portion of the elongate shaft and can include a rotatable and/or translatable cutting element for cutting tissue. Typically, the cutting element is cannulated so that fluid and tissue can pass through it. In some cases, the hand piece is releasably mated to the elongate shaft so that the cutting assembly can be disposed of after each use and the hand piece can be reused. During an arthroscopic procedure, the distal end of the shaft is inserted into a small incision formed in a patient. Suction is applied to the shaver to cause bodily tissue and associated fluids to flow through the cutting assembly and out through a proximal end of the hand piece where the tissue and fluids can be collected in a waste collection container.
In view of the benefits of minimally invasive procedures, it would be desirable to reduce the size profile of shavers to allow arthroscopic shavers to be inserted into the body through smaller access portals. However, cutting elements of current shavers are usually cannulated to allow fluid and excised tissue to pass through, and this limits the effectiveness of such shavers when the size is reduced. More specifically, as the diameter of the cutting element and the elongate shaft are reduced, the components become less stiff and cut tissue can become trapped in the cutting assembly. Even a small mass of tissue can impart a transverse load on the cutting element, which can cause tissue to travel in-between the moving and stationary components and/or cause the cutting surfaces to prematurely wear. This can result in binding and/or ineffective cutting.
The configurations of current devices restrict the ability to reduce the size profile of these shavers in other ways. For example, in devices where the cutting assembly extends proximally through the device, tissue and cut fluid also flows proximally through the cutting assembly such that the space for tissue/fluid to be suctioned out is limited by the diameter of the outer shaft and the diameter of the cutting assembly. At the same time, it is important that the pathway for tissue and fluid flow be large enough to enable efficient removal of bodily matter and/or to enhance visualization of the surgical site.
Accordingly, there remains a need for improved methods and devices for cutting and removing tissue from a body.